Photoshop image

Have an image that use in adverts. We are planning on a xmas campaign.
We are looking for a traditional red and white santa hat to be added to the dog image, you know the sort, red with white fur around the bottom and a white bobble on top so the dog sort of looks like hes ready for xmas party but perhaps not really looking forward to it ( not sure you can do all that by simply adding a hat to a dog but PPH rejected my first simple advert and I'm just adding stuff in the hope that they will pass this one and somebody can do the work for me)
Oh - as to timescale - no great rush - perhaps ion next couple of weeks - certainly before xmas